Aluminum TIG newb questions

I have the PowerTig 225LX and have been playing this morning. I have learned some stuff but now have even more questions for you learned types. Some of this stuff may seem really stupid, but I'd rather ask than keep wondering.

First the machine settings: 30 amps, AC, 2T-w/torch switch, Pulse OFF,
1/16" 2% thoriated, no. 5 gas cup, 100% argon @ 6 LPH.

Type metal: .025 aluminum sheet (Lowes), 4043 1/16" rod.

Questions
I seem to be unable to change the amount of cathotic etching with the AC balance. On a nice consistent .25 inch wide bead the etching is about 2/3 as wide on both sides of the bead, with no apparent change no matter what the setting of the AC balance. Is this normal at lower amps?

When pulse is selected and you use an amperage setting of say 30 amps and the display flashes between 2 numbers, I understand that to indicate the high and the low amperage while pulsing. Why do these numbers wander?

If I set the amps to the lowest setting (23 amps on my machine) with pulse selected will there be any observable difference (will it pulse lower)?

Does the up slope and down slope function in 2T mode utilizing the torch switch? (Ie. ramp up to set amperage and then ramp down or is this only in 4T?)

On initial start I sometimes get a crackle and/or a sputter on the above listed aluminum. Is this caused by my technique or is it something I've not set up correctly? (not enough gas flow, dirty metal/poor quality metal, electrode gap, electrode stickout, torch angle, etc.)

How long should my Argon last? I've got a 160CF bottle that started with 2200lbs of pressure. after 2.5 hours of actual torch lit time @6 LPH I have about 1800lbs of pressure. Is this normal? My mig machine doesn't seem to go thru gas quite as quickly!? (I plan on bubble checking it later)

What is the air speed velocity of an unladen swallow? (african):rolleyes:

I'd appreciate any insight you folks might have.

Best Regards, Zoom

First Zoom,
You need to check the low amp setting again and give more details. That does not sound right.

Second, there are answers to many of your questions if you will read around, especially your manual about the 2T/4T thing...and yes it still functions, but automatically.

Third, please post pictures.

Fourth, Forget about the pulse until you have learned to TIG well or it willl screw you up and cause you a lot of confusion.

Fifth, Any number of things can cause it to crackle and sputter occasionally, including you, and contamination.

Sixth that is not LPH, but LPM, and you are putting out about 13-15 cfh depending upon how you read your meter. If you figure 2.5 hours of torch time, then that is about 35 cu ft of gas consumed roughly and about 20% of the volume. Consumption is dead on I believe.

For practicing on aluminum I would recommend a thicker stock and use the foot pedal. Thicker is much more forgiving and you'll have better puddle control with the pedal.

Also, metal prep makes a big difference. I was having a real hard time till I prepared it right.

Used a 3m disc on a DA to start, then brush with a dedicated stainless brush, and then wipe with rubbing alcohol.

And a photo of some beads. First ever TIGing aluminum!!!
[IMG]http://i161.photobucket.com/albums/t...ig225LX006.jpg[/IMG]
The first ones are at the bottom. Be gentle...:)

The cleaning action I am seeing is not that bad of the pictures at the top. Again, it is thin metal and not as much can be made of it. A lot of times cleaning action more on one side of the weld is attributed to torch angle.

Mark,
Check your Performance email!

zoomie what does your machine sound like when in AC mode? Is it real quiet like DC?

It's much more crisp sounding. Kind of sharp and somewhat louder.

Zoomie,
Got your email, just give me a call tomorrow afternoon if you can, and we can figure it out.

Mark,
I've read quite extensively and some of these things I have asked still haven't become apparent. Thus, the questions listed.
I do agree that the pulse is an added complexity I probably will not be using during my initial forrays into functional joining of metal. On the other hand, not playing with the functions while learning on scrap is alot like telling a kid not go near the water til they learn how to swim. Also, my purpose for farting with the pulse is twofold, 1. to verify the function works and 2. to learn how it effects the welding process. I am very much a full immersion type learner, so I'm gonna dive in head first and keep asking questions! ;)

Oh I checked my argon connections and found and fixed a minor gas leak at the back of the machine. Yeah Liters per Minute, it didn't look right when I typed it. Oh well!
Thanks for all the one on one. I'll call you back after lunch today.

Quote:

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What is the air speed velocity of an unladen swallow? (african)

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In order to maintain air-speed velocity, an african swallow needs to beat its wings forty-three times every second. Not sure about European but carrying coconuts is probably not possible and it's unlikely that one could carry two but it may be possible for two to carry one if they each held onto the husk.

Hey, who's horse is this anyway!

Steve,
I've been laughing for the last 30 seconds. An awesome movie...
Not a lot of weld comments though. Any suggestions (take up bowling perhaps)? :rolleyes: